μὴ κακὸν εὖ ἔρξῃς· σπείρειν ἴσον ἔστ' ἐνὶ πόντῳ → do no good to a bad man; it is like sowing in the sea
ἐπῳδός, ἐπιδικάσιμος, ὠφελήσιμος, ἐπαρωγός, ὠφέλιμος, ἐπίκουρος, σύμμαχος, ἐπίρροθος, ἐριούνιος